Electric meter.



No. 698,668. Patented .Apr. 29, I902.

T. DUNCAN. ELECTRIC METER.

(Application filed Nov. 10, 1899.)

(No Modal.) 6 2 Sheets-Sheet I.

0 O o 0 CZ K 01 WITNESSES: (gaff/:7 R. M @(W 4 W Irv/ r Qy A TTORNE Y.

No. 698,668. Patnted Apr. 29, I902.

T. DUNCAN.

ELECTRIC METER.

(Application filed mvjio, 1899'.

(No Model.) 2 Sheets$heet 2.

Jimmy/ N'IED TATES' THOMAS DUNCAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS 8s HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRIC METER.

SPECIFICATION forming part of Letters Patent No. 698,668, dated April 29, 1902.

Application filed November 10,1899. Serial No. 736,488. (NO model.)

To all whom it may concern.-

Be it known that I, THOMAS DUNCAN, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Meters, (Case No. 66,) of which the following is a specification.

This invention relates to improvements in integrating wattmeters of the induction-motor type for use inalternating-currentsystems of electrical distribution.

The object of the invention is to produce a simplified design which will be capable of economical construction and which at the same time will be accurate in its measurements under all conditions and changes of service and load inductance.

In the accompanying drawings, Figure 1 is a front elevation, partially diagrammatic, of an integrating wattmeter embodying my improvement. Fig. 2 shows the mannerin which the laminze of the magnetic cores of the meter are punched from a sheet of metal without waste. Fig. 3 is a sectional view on line 3 3 of Fig. 1.

A designates the series field-coil of the meter, B its volt or shunt field-coil, and C a disk armature that is mounted to rotate freely upon a spindle C, to which an ordinary registering mechanism R is suitably geared. As herein shown, the volt coil B is mounted above the armature upon the middle portion ofan inverted-U-shaped magnetic core D, the downwardly-projecting poles of which terminate in close proximity to the upper surface of the armature C. A secondary magnetic core D, similar to the core D, is sym-' metrically arranged below the armature,with its poles projecting upwardly into close proximity to the under surface of the armature at points directly opposite the poles of the magnet D, and the series coil A is mounted below the armature between said poles of said magnet D, both the coils and the cores being located, as usual, away from the center of the armature, so that there is no interference with the spindle C, which, in the view shown in Fig. 1, passes behind said coils and cores, as shown in dotted lines in said figure. The coil A is centrally displaced relative to the magnet Dthat is, eccentrically mounted with respect to the central line passing through both poles of the magnet D, as shown most clearly in Fig. 3. The coil A is connected in series in the work-circuit W and the coil in shunt across the line, the self-inductance of the latter coil producing a phase displacement, by reason of which the armatnre will be inductively rotated. As will be understood by those skilled in the art, however, the 'lag produced by the core D will not amount toninety degrees, and to increase such lag to the full quadrature necessary to accurate service under all conditions of load inductance an auxiliary volt-coil B is mounted on the core D and connected in shunt across the work-circuit W in a reverse direction to the main volt-coil B, with the effect of producing a resultant magnetic field lagging the full ninety degrees desired. The usual magnetic drag E serves to maintain the armature rotation proportional to the torque exerted.

In forming the cores D and D U-shapedlaminae cl are punched from sheet metal by a suitable, punchingpress and afterward assembled and secured together in any suitable manner, as by clamping-screws d. These U-shaped punchings d are so shaped that when laid together in oppositelydirected pairs their pole-pieces will exactly interfit with each other, after the manner shown in Fig. 2, so that said laminae may be punched from a strip of metal of proper width without any waste. In consequence of this mode of construction all waste of material in forming the laminated cores is done away with to, volt field-coil B Wound on one core, secof two subscribing Witnesses this 7th day of ondary volt-coil B wound on the other core, November, A. D. 1899.

and series field-coilA mounted eccentric-ally T to the poles of the coi'es, substantially as de- THOMAS DUB scribed. Witnesses:

In, testimony that I claim the foregoing as WM. F. MEYER,

my invention I affix my signature, in presence J. WV. MCKENZIE. 

